Systems and methods for mirroring virtual functions in a chassis configured to receive a plurality of modular information handling systems and a plurality of modular information handling resources

ABSTRACT

A method may include, in a chassis configured to receive a plurality of modular information handling systems and a plurality of modular information handling resources, exposing a first virtual function instantiated on a management processor disposed in the chassis to a switch interfaced between a modular information handling system and the management processor. The method may also include communicating, by the management processor, an input/output request from the modular information handling system received by the first virtual function to at least one of a second virtual function instantiated on a first storage controller communicatively coupled to the management processor and a third virtual function instantiated on a second storage controller communicatively coupled to the management processor. The method may further include receiving, by the management processor, an acknowledgment of completion of the input/output request from at least one of the second virtual function and the third virtual function.

TECHNICAL FIELD

The present disclosure relates in general to information handlingsystems, and more particularly to operation of virtual functions relatedto modular information handling resources in a chassis.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Existing server architectures either provide a single monolithic servercapable of running one operating system (or a single hypervisor runningmultiple virtualized operating systems) and input/output (“I/O”)resources at a time, or bulky blade server chassis providing multipleservers and I/O control modules in a single chassis. A system chassiswith multiple information handling systems with various peripheral andI/O capabilities common to the chassis as a whole may provideadvantages, as it allows a blade server chassis in a small form factor,thereby providing a blade server chassis with a size comparable to thesize of a monolithic server. Implementation of a system chassis withmultiple information handling systems with various peripheral and I/Ocapabilities common to the chassis as a whole presents numerouschallenges.

SUMMARY

In accordance with the teachings of the present disclosure, thedisadvantages and problems associated with mirroring virtual functionshave been reduced or eliminated.

In accordance with embodiments of the present disclosure, a system mayinclude a chassis and a management processor. The chassis may beconfigured to receive a plurality of modular information handlingsystems and a plurality of modular information handling resources. Themanagement processor may be disposed in the chassis and configured to becommunicatively coupled to modular information handling systems receivedin the chassis and further configured to. The management processor mayalso be configured to expose a first virtual function instantiated onthe management processor to a switch interfaced between a modularinformation handling system and the management processor. The managementprocessor may additionally be configured to communicate an input/outputrequest from the modular information handling system received by thefirst virtual function to at least one of a second virtual functioninstantiated on a first storage controller communicatively coupled tothe management processor and a third virtual function instantiated on asecond storage controller communicatively coupled to the managementprocessor. The management processor may further be configured to receivean acknowledgment of completion of the input/output request from atleast one of the second virtual function and the third virtual function.The management processor may also be configured to communicate theacknowledgement to the information handling system via the switch andthe first virtual function.

In accordance with these and other embodiments of the presentdisclosure, a method may include, in a chassis configured to receive aplurality of modular information handling systems and a plurality ofmodular information handling resources, exposing a first virtualfunction instantiated on a management processor disposed in the chassisto a switch interfaced between a modular information handling system andthe management processor. The method may also include communicating, bythe management processor, an input/output request from the modularinformation handling system received by the first virtual function to atleast one of a second virtual function instantiated on a first storagecontroller communicatively coupled to the management processor and athird virtual function instantiated on a second storage controllercommunicatively coupled to the management processor. The method mayfurther include receiving, by the management processor, anacknowledgment of completion of the input/output request from at leastone of the second virtual function and the third virtual function. Themethod may additionally include communicating, by the managementprocessor, the acknowledgement to the information handling system viathe switch and the first virtual function.

Technical advantages of the present disclosure will be apparent to thoseof ordinary skill in the art in view of the following specification,claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and advantagesthereof may be acquired by referring to the following description takenin conjunction with the accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIG. 1 illustrates a block diagram of an example system chassis withmultiple information handling systems and with various peripheral andI/O capabilities common to the chassis as a whole, in accordance withembodiments of the present disclosure;

FIG. 2 illustrates a more detailed block diagram of an example systemconfigured for switches and devices in a multi-root I/O virtualizationenvironment for multiple information handling systems, in accordancewith embodiments of the present disclosure;

FIG. 3 illustrates a virtual stack for I/O communication between aninformation handling system and target storage controllers, inaccordance with embodiments of the present disclosure; and

FIG. 4 illustrates another virtual stack for I/O communication betweenan information handling system and target storage controllers, inaccordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

Preferred embodiments and their advantages are best understood byreference to FIGS. 1 through 4, wherein like numbers are used toindicate like and corresponding parts.

For the purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, entertainment, or other purposes. For example, aninformation handling system may be a personal computer, a personaldigital assistant (PDA), a consumer electronic device, a network storagedevice, or any other suitable device and may vary in size, shape,performance, functionality, and price. The information handling systemmay include memory, one or more processing resources such as a centralprocessing unit (“CPU”) or hardware or software control logic.Additional components of the information handling system may include oneor more storage devices, one or more communications ports forcommunicating with external devices as well as various I/O devices, suchas a keyboard, a mouse, and a video display. The information handlingsystem may also include one or more busses operable to transmitcommunication between the various hardware components.

For the purposes of this disclosure, information handling resources maybroadly refer to any component system, device or apparatus of aninformation handling system, including without limitation processors,busses, memories, I/O devices and/or interfaces, storage resources,network interfaces, motherboards, electro-mechanical devices (e.g.,fans), displays, and power supplies.

For the purposes of this disclosure, computer-readable media may includeany instrumentality or aggregation of instrumentalities that may retaindata and/or instructions for a period of time. Computer-readable mediamay include, without limitation, storage media such as a direct accessstorage device (e.g., a hard disk drive or floppy disk), a sequentialaccess storage device (e.g., a tape disk drive), compact disk, CD-ROM,DVD, random access memory (“RAM”), read-only memory (“ROM”),electrically erasable programmable read-only memory (“EEPROM”), and/orflash memory; as well as communications media such as wires, opticalfibers, microwaves, radio waves, and other electromagnetic and/oroptical carriers; and/or any combination of the foregoing.

Information handling systems often use an array of physical storageresources (e.g., disk drives), such as a Redundant Array of IndependentDisks (“RAID”), for example, for storing information. Arrays of physicalstorage resources typically utilize multiple disks to perform input andoutput operations and can be structured to provide redundancy which mayincrease fault tolerance. Other advantages of arrays of physical storageresources may be increased data integrity, throughput and/or capacity.In operation, one or more physical storage resources disposed in anarray of physical storage resources may appear to an operating system asa single logical storage unit or “logical unit.” Implementations ofphysical storage resource arrays can range from a few physical storageresources disposed in a chassis, to hundreds of physical storageresources disposed in one or more separate storage enclosures.

FIG. 1 illustrates a block diagram of an example system 100 having achassis 101 with multiple information handling systems 102 and withvarious peripheral and I/O capabilities common to chassis 101 as awhole, in accordance with embodiments of the present disclosure. Asdepicted in FIG. 1, system 100 may comprise a chassis 101 including aplurality of information handling systems 102, a mid-plane 106, one ormore switches 110, one or more chassis management controllers 112, anetwork interface 116, one or more slots 120, one or more cables 124,one or more storage interfaces 126, a disk drive backplane 128, aplurality of disk drives 130, an optical media drive 132, akeyboard-video-mouse (“KVM”) interface 134, and a user interface 136.

An information handling system 102 may generally be operable to receivedata from and/or communicate data to one or more disk drives 130 and/orother information handling resources of chassis 101 via mid-plane 106and/or switches 110. In certain embodiments, an information handlingsystem 102 may be a server. In such embodiments, an information handlingsystem may comprise a blade server having modular physical design. Inthese and other embodiments, an information handling system 102 maycomprise an M class server. As depicted in FIG. 1, an informationhandling system 102 may include a processor 103 and one or more switchinterfaces 104 communicatively coupled to processor 103.

A processor 103 may include any system, device, or apparatus configuredto interpret and/or execute program instructions and/or process data,and may include, without limitation, a microprocessor, microcontroller,digital signal processor (“DSP”), application specific integratedcircuit (“ASIC”), or any other digital or analog circuitry configured tointerpret and/or execute program instructions and/or process data. Insome embodiments, processor 103 may interpret and/or execute programinstructions and/or process data stored in a memory, a disk drive 130,and/or another component of system 100.

A switch interface 104 may comprise any system, device, or apparatusconfigured to provide an interface between its associated informationhandling system 102 and switches 110. In some embodiments, switches 110may comprise Peripheral Component Interconnect Express (“PCIe”)switches, in which case a switch interface 104 may comprise a switchcard configured to create a PCIe-compliant interface between itsassociated information handling system 102 and switches 110. In otherembodiments, a switch interface 104 may comprise an interposer. Use ofswitch interfaces 104 in information handling systems 102 may allow forminimal changes to be made to traditional servers (e.g., M classservers) while supporting the overall system architecture disclosedherein. Although FIG. 1 depicts an implementation including a singleswitch interface 104 per information handling system 102, in someembodiments each information handling system 102 may include a pluralityof switch interfaces 104 for redundancy, high availability, and/or otherreasons.

Mid-plane 106 may comprise any system, device, or apparatus configuredto interconnect modular information handling systems 102 withinformation handling resources. Accordingly, mid-plane 106 may includeslots and/or connectors configured to receive information handlingsystems 102, switches 110, chassis management controllers 112, storagecontrollers 114, network interface 116, optical media drive 132, KVMinterface 134, user interface 136, and/or other information handlingresources. In one embodiment, mid-plane 106 may include a single boardconfigured to interconnect modular information handling systems 102 withinformation handling resources. In another embodiment, mid-plane 106 mayinclude multiple boards configured to interconnect modular informationhandling systems 102 with information handling resources. In yet anotherembodiment, mid-plane 106 may include cabling configured to interconnectmodular information handling systems 102 with information handlingresources.

A switch 110 may comprise any system, device, or apparatus configured tocouple information handling systems 102 to storage controllers 114(e.g., via mid-plane 106) and slots 120 and perform switching betweeninformation handling systems 102 and various information handlingresources of system 100, including storage controllers 114 and slots120. In certain embodiments, a switch 110 may comprise a PCIe switch. Inother embodiments, a switch may comprise a generalized PC bus switch, anInfiniband switch, or other suitable switch. As shown in FIG. 1, chassis101 may include a plurality of switches 110. In such embodiments,switches 110 may operate in a redundant mode for shared devices (e.g.,storage controllers 114 and/or devices coupled to slots 120) and innon-redundant mode for non-shared/zoned devices. As used herein, shareddevices may refer to those which may be visible to more than oneinformation handling system 102, while non-shared devices may refer tothose which are visible to only a single information handling system102. In some embodiments, mid-plane 106 may include a single switch 110.

A chassis management controller 112 may be any system, device, orapparatus configured to facilitate management and/or control of system100, its information handling systems 102, and/or one or more of itscomponent information handling resources. A chassis managementcontroller 112 may be configured to issue commands and/or other signalsto manage and/or control information handling system 102 and/orinformation handling resources of system 100. A chassis managementcontroller 112 may comprise a microprocessor, microcontroller, DSP,ASIC, field programmable gate array (“FPGA”), EEPROM, or any combinationthereof. As shown in FIG. 1, a chassis management controller 112 may becoupled to mid-plane 106. Also as shown in FIG. 1, system 100 mayinclude a plurality of chassis management controllers 112, and in suchembodiments, chassis management controllers 112 may be configured asredundant. In some embodiments, a chassis management controller 112 mayprovide a user interface and high level controls for management ofswitches 110, including configuring assignments of individualinformation handling systems 102 to non-shared information handlingresources of system 100. In these and other embodiments, a chassismanagement controller may define configurations of the storage subsystem(e.g., storage controllers 114, storage interfaces 126, disk drives 130,etc.) of system 100. For example, a chassis management controller mayprovide physical function configuration and status information thatwould normally occur at the driver level in traditional serverimplementations. Examples of physical functions include disk drivediscovery and status, RAID configuration and logical volume mapping.

In addition or alternatively, a chassis management controller 112 mayalso provide a management console for user/administrator access to thesefunctions. For example, a chassis management controller 112 mayimplement Web Services Management (“WS-MAN”) or another suitablemanagement protocol permitting a user to remotely access a chassismanagement controller 112 to configure system 100 and its variousinformation handling resources. In such embodiments, a chassismanagement controller 112 may interface with a network interfaceseparate from network interface 116, thus allowing for “out-of-band”control of system 100, such that communications to and from chassismanagement controller 112 are communicated via a management channelphysically isolated from an “in-band” communication channel with networkinterface 116. Thus, for example, if a failure occurs in system 100 thatprevents an administrator from interfacing with system 100 via networkinterface 116 and/or user interface 136 (e.g., operating system failure,power failure, etc.), the administrator may still be able to monitorand/or manage system 100 (e.g., to diagnose problems that may havecaused failure) via a chassis management controller 112. In the same oralternative embodiments, chassis management controller 112 may allow anadministrator to remotely manage one or more parameters associated withoperation of system 100 and its various information handling resources(e.g., power usage, processor allocation, memory allocation, securityprivileges, etc.). Although FIG. 1 depicts chassis 101 as having twochassis management controllers 112, chassis 101 may include any suitablenumber of chassis management controllers 112.

A storage controller 114 may include any system, apparatus, or deviceoperable to manage the communication of data between one or more ofinformation handling systems 102 and one or more of disk drives 130. Incertain embodiments, a storage controller 114 may provide functionalityincluding, without limitation, disk aggregation and redundancy (e.g.,RAID), I/O routing, and error detection and recovery. As shown in FIG.1, a storage controller 114 may be coupled to a connector on a switch110. Also as shown in FIG. 1, system 100 may include a plurality ofstorage controllers 114, and in such embodiments, storage controllers114 may be configured as redundant. In addition or in the alternative,storage controllers 114 may in some embodiments be shared among two ormore information handling systems 102. As also shown in FIG. 1, eachstorage controller 114 may be coupled to one or more storage interfaces126 via cables 124. For example, in some embodiments, each storagecontroller 114 may be coupled to a single associated storage interface126 via a cable 124. In other embodiments, each storage controller 114may be coupled to two or more storage interfaces 126 via a plurality ofcables 124, thus permitting redundancy as shown in FIG. 1. Storagecontrollers 114 may also have features supporting shared storage andhigh availability. For example, in PCIe implementations, a unique PCIeidentifier may be used to indicate shared storage capability andcompatibility in system 100.

As depicted in FIG. 1, switch 110 may have coupled thereto one or moreslots 120. A slot 120 may include any system, device, or apparatusconfigured to allow addition of one or more expansion cards to chassis101 in order to electrically couple such expansion cards to a switch110. Such slots 120 may comprise any suitable combination of full-heightrisers, full-height slots, and low-profile slots. A full-height risermay include any system, device, or apparatus configured to allowaddition of one or more expansion cards (e.g., a full-height slot)having a physical profile or form factor with dimensions thatpractically prevent such expansion cards to be coupled in a particularmanner (e.g., perpendicularly) to mid-plane 106 and/or switch 110 (e.g.,the proximity of information handling resources in chassis 101 preventsphysical placement of an expansion card in such a manner). Accordingly,a full-height riser may itself physically couple with a low-profile tomid-plane 106, a switch 110, or another component, and full-height cardsmay then be coupled to full-height slots of a full-height riser. On theother hand, low-profile slots may be configured to couple low-profileexpansion cards to switches 110 without the need for a full-heightriser.

Slots 120 may also include electrically conductive elements (e.g., edgeconnectors, traces, etc.) allowing for expansion cards inserted intoslots 120 to be electrically coupled to switches 110. In operation,switches 110 may manage switching of communications between individualinformation handling systems 102 and expansion cards coupled to slots120. In some embodiments, slots 120 may be nonshared (e.g., each slot120 is associated with a single information handling system 102). Inother embodiments, one or more of slots 120 may be shared among two ormore information handling systems 102. In these and other embodiments,one or more slots 120 may be configured to be compatible with PCIe,generalized PC bus switch, Infiniband, or other suitable communicationspecification, standard, or protocol.

Network interface 116 may include any suitable system, apparatus, ordevice operable to serve as an interface between chassis 101 and anexternal network (e.g., a local area network or other network). Networkinterface 116 may enable information handling systems 102 to communicatewith the external network using any suitable transmission protocol(e.g., TCP/IP) and/or standard (e.g., IEEE 802.11, Wi-Fi). In certainembodiments, network interface 116 may include a network interface card(“NIC”). In the same or alternative embodiments, network interface 116may be configured to communicate via wireless transmissions. In the sameor alternative embodiments, network interface 116 may provide physicalaccess to a networking medium and/or provide a low-level addressingsystem (e.g., through the use of Media Access Control addresses). Insome embodiments, network interface 116 may be implemented as a localarea network (“LAN”) on motherboard (“LOM”) interface.

In some embodiments, various components of chassis 101 may be coupled toa planar. For example, a planar may interconnect switches 110, chassismanagement controller 112, storage controllers 114, network interface116, optical media drive 132, KVM interface 134, user interface 136,and/or other modular information handling resources of chassis 101 tomid-plane 106 of system 100. Accordingly, such planar may include slotsand/or connectors configured to interconnect with such informationhandling resources.

Storage interfaces 126 may include any system, device, or apparatusconfigured to facilitate communication between storage controllers 114and disk drives 130. For example, a storage interface may serve topermit a relatively small number of communication links (e.g., two)between storage controllers 114 and storage interfaces 126 tocommunicate with a greater number (e.g., 25) of disk drives 130. Thus, astorage interface 126 may provide a switching mechanism and/or diskdrive addressing mechanism that allows an information handling system102 to communicate with numerous disk drives 130 via a limited number ofcommunication links and/or channels. Accordingly, a storage interface126 may operate like an Ethernet hub or network switch that allowsmultiple systems to be coupled using a single switch port (or relativelyfew switch ports). A storage interface 126 may be implemented as anexpander (e.g., a Serial Attached SCSI (“SAS”) expander), an Ethernetswitch, a FibreChannel switch, an Internet Small Computer SystemInterface (iSCSI) switch, or any other suitable switch. In order tosupport high availability storage, system 100 may implement a pluralityof redundant storage interfaces 126, as shown in FIG. 1.

Disk drive backplane 128 may comprise any system, device, or apparatusconfigured to interconnect modular storage interfaces 126 with modulardisk drives 130. Accordingly, disk drive backplane 128 may include slotsand/or connectors configured to receive storage interfaces 126 and/ordisk drives 130. In some embodiments, system 100 may include two or morebackplanes, in order to support differently-sized disk drive formfactors. To support redundancy and high availability, a backplane 128may be configured to receive a plurality (e.g., two) of storageinterfaces 126 which couple two storage controllers 114 to each diskdrive 130.

Each disk drive 130 may include computer-readable media (e.g., magneticstorage media, optical storage media, opto-magnetic storage media,and/or other type of rotating storage media, flash memory, and/or othertype of solid state storage media) and may be generally operable tostore data and/or programs (e.g., one or more operating systems and/orone or more application programs). Although disk drives 130 are depictedas being internal to chassis 101 in FIG. 1, in some embodiments, one ormore disk drives may be located external to chassis 101 (e.g., in one ormore enclosures external to chassis 101).

Optical media drive 132 may be coupled to mid-plane 106 and may includeany suitable system, apparatus, or device configured to read data fromand/or write data to an optical storage medium (e.g., a compact disc,digital versatile disc, blue laser medium, and/or other optical medium).In certain embodiments, optical media drive 132 may use laser light orother electromagnetic energy to read and/or write data to an opticalstorage medium. In some embodiments, optical media drive 132 may benonshared and may be user-configurable such that optical media drive 132is associated with a single information handling system 102.

KVM interface 134 may be coupled to mid-plane 106 and may include anysuitable system, apparatus, or device configured to couple to one ormore of a keyboard, video display, and mouse and act as a switch betweenmultiple information handling systems 102 and the keyboard, videodisplay, and/or mouse, thus allowing a user to interface with aplurality of information handling systems 102 via a single keyboard,video display, and/or mouse.

User interface 136 may include any system, apparatus, or device viawhich a user may interact with system 100 and its various informationhandling resources by facilitating input from a user allowing the userto manipulate system 100 and output to a user allowing system 100 toindicate effects of the user's manipulation. For example, user interface136 may include a display suitable for creating graphic images and/oralphanumeric characters recognizable to a user, and may include, forexample, a liquid crystal display, cathode ray tube, a plasma screen,and/or a digital light processor projection monitor. In certainembodiments, such a display may be an integral part of chassis 101 andreceive power from power supplies (not explicitly shown) of chassis 101,rather than being coupled to chassis 101 via a cable. In someembodiments, such display may comprise a touch screen device capable ofreceiving user input, wherein a touch sensor may be mechanically coupledor overlaid upon the display and may comprise any system, apparatus, ordevice suitable for detecting the presence and/or location of a tactiletouch, including, for example, a resistive sensor, capacitive sensor,surface acoustic wave sensor, projected capacitance sensor, infraredsensor, strain gauge sensor, optical imaging sensor, dispersive signaltechnology sensor, and/or acoustic pulse recognition sensor. In theseand other embodiments, user interface 136 may include other userinterface elements (e.g., a keypad, buttons, and/or switches placed inproximity to a display) allowing a user to provide input to system 100.User interface 136 may be coupled to chassis management controllers 112and/or other components of system 100, and thus may allow a user toconfigure various information handling resources of system 100 (e.g.,assign individual information handling systems 102 to particularinformation handling resources).

When a system (e.g., system 100) is architected so as to allowinformation handling resources (e.g., PCIe adapters coupled to slots120) to be located in a chassis having shared resources such that theinformation handling resources may be assigned to one informationhandling system or shared among a plurality of information handlingresources, challenges may arise when needing to service an informationhandling resource.

Shared resources or devices, such as PCIe adapters coupled to slots 120,may be virtualized across multiple information handling systems 102.Non-shared resources or devices may be partitioned such that they arevisible only to a single information handling system 102 at a time.Chassis management controller 112 may be configured to handle routingand switching through switches 110 to affect sharing of a resource tomultiple information handling systems 102 or to affect dedicatedassignment of a resource to a single information handling system 102.

FIG. 2 illustrates a more detailed block diagram of example system 100configured for switches and devices in a multi-root I/O virtualization(“IOV”) environment for multiple information handling systems 102 inaccordance with embodiments of the present disclosure.

As shown in FIG. 2, chassis 101 may include a management processor 248communicatively coupled to one or more of chassis management controller112 and switches 110. Management processor 248 may be any system,device, or apparatus configured to facilitate management and/or controlof switches 110. Management processor 248 may be configured to issuecommands and/or other signals to switches 110. Management processor 248may comprise a microprocessor, microcontroller, DSP, ASIC, EEPROM, orany combination thereof. In one embodiment, management processor 248 mayrun a Linux operating system and includeapplication-programming-interfaces (“APIs”) for supporting configurationof IOV in system 100 for sharing devices connected to slots 234 ofchassis 101 to multiple information handling systems 102. The APIs ofmanagement processor 248 may provide the interface to chassis managementcontroller 112 for configuring IOV. Management processor 248 may beconfigured to manage both switches 110. In one embodiment, managementprocessor 248 may be communicatively coupled to an Ethernet managementfabric 240 and to information handling systems 102. In anotherembodiment, chassis management controller 112 may be communicativelycoupled to the information handling systems 102 through Ethernetmanagement fabric 240. Chassis management controller 112 may be directlycommunicatively coupled to the Ethernet management fabric 240 orthrough, for example, management processor 248.

Although FIG. 2 depicts management controller 248 operable to facilitatemanagement and/or control of switches 110, in some embodiments of thepresent disclosure, one or more chassis management controllers 112 maybe configured to perform the functionality of management processor 248,in which a management processor 248 independent of the chassismanagement controllers 112 may not be present.

Chassis 101 may include multiple information handling systems 102.Chassis 101 may include any suitable number of information handlingsystems 102. In some embodiments, information handling systems 102 maybe referred to as “blades”.

Each information handling system 102 may include switch interfaces 104,as described in association with FIG. 1. Information handling systems102 may include a basic input-output system 246 (“BIOS”) which may beimplemented, for example, on firmware for execution by the informationhandling system. Information handling system 102 may access BIOS 246upon, for example, start-up of information handling system 102 toinitialize interoperation with the rest of chassis 101.

Information handling system 102 may include a remote access controller244. Remote access controller 244 may be implemented by, for example, amicroprocessor, microcontroller, DSP, ASIC, EEPROM, or any combinationthereof. Remote access controller 244 may be configured to communicatewith one or more of chassis management controller 112 and managementprocessor 248. Such communication may be made, for example, throughEthernet management fabric 240. Remote access controller 244 may beconfigured to provide out-of-band management facilities for managementof information handling system 102. Such management may be made byelements of chassis 101 even if information handling system 102 ispowered off or powered to a standby state. Remote access controller 244may include a processor, memory, and network connection separate fromthe rest of information handling system 102. In certain embodiments,remote access controller 244 may include or may be an integral part of abaseboard management controller (BMC), Dell Remote Access Controller(DRAC) or an Integrated Dell Remote Access Controller (iDRAC). Remoteaccess controller 244 may be communicatively coupled to BIOS 246.

Switches 110 may contain PCIe cards instead of the typical bladeEthernet, Fibre Channel or InfiniBand cards. Switch interfaces 104 ofthe information handling systems 102 may couple to switches 110 throughthe switch interfaces 104 of switches 110. Switches 110 may coupleinformation handling systems 102 to slots 234. Slots 234 may include oneor more of the slots 120 of FIG. 1 in any suitable combination.

In one embodiment, each of information handling systems 102 may becommunicatively coupled to each of switches 110 through one of switchinterfaces 104 resident on the information handling system 102. Forexample, information handling system 102 a may be communicativelycoupled to switch 110 a through switch interface 104 a and to switch 110b through switch interface 104 b. Information handling system 102 b maybe communicatively coupled to switch 110 a through switch interface 104c and to switch 110 b through switch interface 104 d. Thus, each ofswitches 110 may provide its switching fabric to each of informationhandling systems 102 in order to route the given information handlingsystem 102 to respective slots 234 associated with the switch 110.

Slots 234 may be configured to couple to associated devices 236, thoughfewer devices may be present than the associated capacity of chassis101. Chassis 101 may include any suitable number of slots 234. In someembodiments, devices 236 may include PCIe-based cards or devices. Eachsuch device 236 may represent an information handling resource to beselectively shared among multiple information handling systems 102 ordedicated to a single information handling system 102. A device 236 maycomprise, for example, a RAID controller, network card, or otherinformation handling resource. Furthermore, a device 236 may include aspecific shared component such as a NIC. Devices 236 may includemanagement information or circuitry configured to provide information tochassis 101 regarding the operation or specification of device 236. Forexample, a device 236 may include EEPROM 238 containing suchinformation.

In order to support IOV, the driver and firmware of device 236 mayinclude support for single root IOV (SR-IOV). To maintain routes betweengiven information handling systems 102 and slots 234, switches 110 mayinclude virtual hierarchies from slots 234 to information handlingsystems 102. Particular functions, such as virtual functions or sharedfunctions, for SR-IOV for a given device 236 may be mapped in switch110, providing behavior similar to multiple-root IOV (MR-IOV). Thus, insuch case, a switch 110 may be considered a Multi-Root Aware (MRA)switch which bridges MR-IOV to SR-IOV so that SR-IOV virtual functionsmay be exposed to a mode as physical function, such that an informationhandling system 102 is not aware that a given device 236 is shared. Inone embodiment, wherein device 236 contains multiple informationhandling resources such as a NIC and USB interface, a function may beprovided for each such information handling resource. Thus, from theperspective of information handling systems 102 such multipleinformation handling resources may appear to be separate and unrelated.A given slot 234 or device 236 which has been virtualized may beaccessed by two or more virtual functions, which allows the sharing ofthe resource. Physical functions, as opposed to the above-describedvirtual functions or shared functions, may be mapped or stored inmanagement processor 248. A physical function representing aninformation handling resource may be provided to a single informationhandling system 102. In cases where a device 236 contains multipleinformation handling resources, individual physical functions may beprovided for each such resource. Multiple instances of a virtualfunction may be provided to multiple information handling systems 102.If, for example, multiple information handling systems 102 are sharing adevice 236, then access to device 236 may be divided into multiplevirtual NICs using virtual functions, each of which are mapped byswitches 110 to the respective information handling system 102.Furthermore, specific APIs for accessing a given device 236 may bemapped or stored in management processor 248. Chassis managementcontroller 112 may be configured to access these physical functions orAPIs in management processor 248.

In some embodiments of system 100, many devices 236 of the same orsimilar functionality may be coupled to slots 234. In addition, suchdevices 236 may be shared among multiple information handling systems102 or may be dedicated to a single information handling system 102.When a device 236 is shared among multiple information handling systems102, and such device 236 becomes degraded (e.g., fails or becomesoverused beyond its capacity), such degradation can result in loss offunctionality of one or more of the information handling systems 102associated with the device 236, all the while a device 236 with the samefunctionality may be sitting idle or well under capacity in another slot234. Thus, a mechanism for dynamically allocating devices 236 toinformation handling systems 102 may be desirable.

Because information handling resources, such as those in devices 236coupled to slots 234, are not located within an information handlingsystem 102, but rather in a shared chassis using switches 110 tovirtualize and route I/O communications among selected informationhandling systems 102, allocation of such information handling resourcesmay not be directly controlled by an associated information handlingsystem 102. Consequently, allocation of information handling resourcessuch as devices 236 with information handling systems 102 in chassis 101may be conducted by chassis management controller 112. As described ingreater detail below, chassis management controller 112 may beconfigured to allocate or otherwise direct other components of chassis101 to allocate devices 236 to information handling systems 102. It isnoted that while the functionality described herein contemplatesvirtualization for shared devices 236, the functionality describedherein may also be extended to nonshared devices as well.

As shown in FIG. 2, system chassis 101 may include internal switchingfabrics (e.g., Fabric A and Fabric B). In the embodiments represented byFIG. 2, Fabric A is associated with switch 110 a (labeled “Switch 1”)and Fabric B is associated with switch 110 b (labeled “Switch 2”).Although not depicted in FIG. 2, storage controllers 114 may each beassociated with a particular switching fabric of chassis 101 (e.g.,based upon a slot or connectors via which a particular storagecontroller 114 is coupled to mid-plane 106).

Similarly, to maintain routes between given information handling systems102 and storage controllers 114, switches 110 may include virtualhierarchies from storage controllers 114 such that particular functions,such as virtual functions or shared functions, for SR-IOV for a givenstorage controller 114 may be mapped in switch 110, providing behaviorsimilar to MR-IOV. Although not depicted in FIG. 2, storage controllers114 may each be associated with a particular switching fabric of chassis101 (e.g., based upon a slot or connector via which a particular storagecontroller 114 is coupled to mid-plane 106). Thus, similar to devices236, a given storage controller 114 which has been virtualized may beaccessed by two or more virtual functions, which allows the sharing ofthe resource.

This architecture may allow for high availability and/or data mirroringto disk drives communicatively coupled to devices 236 and storagecontrollers 114 via two different I/O mechanisms. For example, a storagecontroller 114 may comprise a RAID storage controller while a device 236may comprise an iSCSI storage controller coupled to disk drives 130internal to chassis 101 or other disk drives external and/or remote fromchassis 101. As shown in FIG. 3, which depicts a virtual stack 300 forI/O communication between an information handling system 102 and targetstorage controllers, each of a storage controller 114 and a device 236which comprises a storage controller may expose virtual functions tomanagement processor 248. For example, the virtual function of storagecontroller 114 may expose a virtual disk and/or logical unit of astorage resource to management processor 248, while the virtual functionof device 236 may expose an iSCSI host bus adapter (HBA) to managementprocessor 248. Management processor 248 may mirror the two virtualfunctions and expose a single resulting virtual function to a switch110, thus providing a communications pathway between the singleresulting virtual function and one or more information handling systems102. I/O communicated from an information handling system 102 tomanagement processor 248 may be communicated to each of the mirroredvirtual functions associated with storage controller 114 and device 236.

In order to write data to the mirrored storage controller 114 and device236, a write request may be communicated from an information handlingsystem 102 to management processor 248 via a switch 110. Managementprocessor 248 may duplicate the write request, sending the request tomirrored virtual functions for each of a device 236 and a storagecontroller 114. Once the individual write requests have completed, eachof storage controller 114 and device 236 may communicate anacknowledgement to the management controller via their respectivevirtual functions. Once each acknowledgement has been received,management processor 248 may communicate an acknowledgment of completionto the information handling system 102 originating the write request,again via a switch 110 and the virtual function exposed by managementprocessor 248 to such switch 110.

As for a read request, the read request may be communicated from aninformation handling system 102 to management processor 248 via a switch110. In some embodiments, management processor 248 may divide the readrequest into two parts (e.g., forming two separate read requests seekingdifferent portions of the data responsive to the read request),communicating one part to each of a device 236 and a storage controller114. Each of storage controller 114 and device 236 may respond tomanagement processor 248 (e.g., via their respective mirrored virtualfunctions) with data responsive to the part of the read requestcommunicated to it. Management processor 248 may combine the datareceived from device 236 and storage controller 114 and communicate suchdata to the information handling system 102 originating the readrequest, again via a switch 110 and the virtual function exposed bymanagement processor 248 to such switch 110.

In an alternative embodiment, the read request may not be divided intotwo parts by management processor 248, and instead, management processor248 will forward the read request to one of storage controller 114 ordevice 236, not both. For example, during normal operation, readrequests may be forwarded from management processor 248 to storagecontroller 114, and read requests may be forwarded from managementprocessor 248 to device 236 only when storage controller 114 experiencesa failure condition.

Alternatively to the communication stack shown in FIG. 3, highavailability and/or data mirroring may also be accomplished by mirroringcommunications on two storage controllers 114. To that end, FIG. 4depicts another virtual stack 400 for I/O communication between aninformation handling system 102 and target storage controllers 114,wherein each of two storage controllers 114 may expose virtual functionsto management processor 248. For example, the virtual functions ofstorage controller 114 may each expose a respective virtual disk and/orlogical unit of a storage resource to management processor 248.Management processor 248 may mirror the two virtual functions and exposea single resulting virtual function to a switch 110, thus providing acommunications pathway between the single resulting virtual function andone or more information handling systems 102. I/O communicated from aninformation handling system 102 to management processor 248 may becommunicated to each of the mirrored virtual functions associated withstorage controllers 114.

In order to write data to the mirrored storage controllers 114, a writerequest may be communicated from an information handling system 102 tomanagement processor 248 via a switch 110. Management processor 248 mayduplicate the write request, sending the request to mirrored virtualfunctions for each of storage controllers 114. Once the individual writerequests have completed, each of storage controllers 114 may communicatean acknowledgement to the management controller via their respectivevirtual functions. Once each acknowledgement has been received,management processor 248 may communicate an acknowledgment of completionto the information handling system 102 originating the write request,again via a switch 110 and the virtual function exposed by managementprocessor 248 to such switch 110.

As for a read request, the read request may be communicated from aninformation handling system 102 to management processor 248 via a switch110. In some embodiments, management processor 248 may divide the readrequest into two parts (e.g., forming two separate read requests seekingdifferent portions of the data responsive to the read request),communicating one part to each of storage controllers 114. Each ofstorage controllers 114 may respond to management processor 248 (e.g.,via their respective mirrored virtual functions) with data responsive tothe part of the read request communicated to it. Management processor248 may combine the data received from storage controllers 114 andcommunicate such data to the information handling system 102 originatingthe read request, again via a switch 110 and the virtual functionexposed by management processor 248 to such switch 110.

In an alternative embodiment, the read request may not be divided intotwo parts by management processor 248, and instead, management processor248 will forward the read request to one of storage controllers 114, notboth. For example, during normal operation, read requests may beforwarded from management processor 248 to a first storage controller114, and read requests may be forwarded from management processor 248 toa second storage controller 114 only when the first storage controller114 experiences a failure condition.

Although the present disclosure has been described in detail, it shouldbe understood that various changes, substitutions, and alterations canbe made hereto without departing from the spirit and the scope of thedisclosure as defined by the appended claims.

What is claimed is:
 1. A system comprising: a chassis configured toreceive a plurality of modular information handling systems and aplurality of modular information handling resources; a managementprocessor disposed in the chassis and configured to be communicativelycoupled to modular information handling systems received in the chassisand further configured to: expose a first virtual function instantiatedon the management processor to a switch interfaced between a modularinformation handling system and the management processor; communicate aninput/output request from the modular information handling systemreceived by the first virtual function to at least one of: a secondvirtual function instantiated on a first storage controllercommunicatively coupled to the management processor; and a third virtualfunction instantiated on a second storage controller communicativelycoupled to the management processor; receive an acknowledgment ofcompletion of the input/output request from at least one of the secondvirtual function and the third virtual function; and communicate theacknowledgement to the information handling system via the switch andthe first virtual function.
 2. The system of claim 1, the switchcomprising a Peripheral Component Interconnect Express switch.
 3. Thesystem of claim 1, wherein the first storage controller comprises aRedundant Array of Inexpensive Disks controller and the second storagecontroller comprises an Internet Small Computer System Interfacecontroller.
 4. The system of claim 1, wherein the first storagecontroller comprises a first Redundant Array of Inexpensive Diskscontroller and the second storage controller comprises a secondRedundant Array of Inexpensive Disks controller.
 5. The system of claim1, wherein communicating the input/output request comprisescommunicating the input/output request from the modular informationhandling system received by the first virtual function to both of thesecond virtual function and the third virtual function.
 6. The system ofclaim 1, wherein communicating the input/output request comprisescommunicating the input/output request from the modular informationhandling system received by the first virtual function to: the secondvirtual function and not the third virtual function if the first storagecontroller is not in a failure condition; and the third virtual functionif the first storage controller is in a failure condition.
 7. The systemof claim 1, wherein the input/output request is a write request.
 8. Thesystem of claim 7, wherein: communicating the input/output requestcomprises communicating the write request to the second virtual functionand the third virtual function; and receiving the acknowledgment ofcompletion of the input/output request comprises receiving theacknowledgment from both of the second virtual function and the thirdvirtual function.
 9. The system of claim 1, wherein the input/outputrequest is a read request.
 10. The system of claim 9, wherein:communicating the input/output request comprises: dividing the readrequest into a first part and a second part; communicating the firstpart to the second virtual function; communicating the second part tothe third virtual function; and receiving the acknowledgment ofcompletion of the input/output request comprises: receiving dataresponsive to the first part of the read request from the second virtualfunction; and receiving data responsive to the second part of the readrequest from the third virtual function.
 11. A method comprising: in achassis configured to receive a plurality of modular informationhandling systems and a plurality of modular information handlingresources, exposing a first virtual function instantiated on amanagement processor disposed in the chassis to a switch interfacedbetween a modular information handling system and the managementprocessor; communicating, by the management processor, an input/outputrequest from the modular information handling system received by thefirst virtual function to at least one of: a second virtual functioninstantiated on a first storage controller communicatively coupled tothe management processor; and a third virtual function instantiated on asecond storage controller communicatively coupled to the managementprocessor; receiving, by the management processor, an acknowledgment ofcompletion of the input/output request from at least one of the secondvirtual function and the third virtual function; and communicating, bythe management processor, the acknowledgement to the informationhandling system via the switch and the first virtual function.
 12. Themethod of claim 11, the switch comprising a Peripheral ComponentInterconnect Express switch.
 13. The method of claim 11, wherein thefirst storage controller comprises a Redundant Array of InexpensiveDisks controller and the second storage controller comprises an InternetSmall Computer System Interface controller.
 14. The method of claim 11,wherein the first storage controller comprises a first Redundant Arrayof Inexpensive Disks controller and the second storage controllercomprises a second Redundant Array of Inexpensive Disks controller. 15.The method of claim 11, wherein communicating the input/output requestcomprises communicating the input/output request from the modularinformation handling system received by the first virtual function toboth of the second virtual function and the third virtual function. 16.The method of claim 11, wherein communicating the input/output requestcomprises communicating the input/output request from the modularinformation handling system received by the first virtual function to:the second virtual function and not the third virtual function if thefirst storage controller is not in a failure condition; and the thirdvirtual function if the first storage controller is in a failurecondition.
 17. The method of claim 11, wherein the input/output requestis a write request.
 18. The method of claim 17, wherein: communicatingthe input/output request comprises communicating the write request tothe second virtual function and the third virtual function; andreceiving the acknowledgment of completion of the input/output requestcomprises receiving the acknowledgment from both of the second virtualfunction and the third virtual function.
 19. The method of claim 11,wherein the input/output request is a read request.
 20. The method ofclaim 19, wherein: communicating the input/output request comprises:dividing the read request into a first part and a second part;communicating the first part to the second virtual function; andcommunicating the second part to the third virtual function; andreceiving the acknowledgment of completion of the input/output requestcomprising: receiving data responsive to the first part of the readrequest from the second virtual function; and receiving data responsiveto the second part of the read request from the third virtual function.